1.A. Field of the Invention
The explosive growth of intercommunication between computers over the Internet has created a consequential need for means to monitor networks while they are working, in order to assure that the communication flows stay within acceptable limits of both speed and quality. To assure and measure the connections means that the communications flowing through them must be monitored and the communication flow analyzed.
Monitoring and analyzing the communication flows requires both physical and logical assessment. Physical assessment must test each of the several criteria (e.g. voltage drop, baud, clarity) that define a particular connection's physical constraints; while logical assessment must similarly test each of the several criteria (e.g. routing, authorization, timing) that define a particular communication's logical constraints. Typically, network evaluation was done by reviewing communications logs; more recently, however, it has become a normal procedure to tap into the signal flow over a connection being analyzed.
One problem that had to be solved, for both electrical/copper and optical/fiber connections, was how to tap into the communication flow without interfering with the traffic that was passing through the connection being tapped. Physically, any tap was a potential interference (either from a drop in potential or timing delay); logically, a tap could become an unsought and unwanted network termination. In perhaps no other field is the Heisenberg principle (that the act of observation changes the behavior of whatever is being observed) more keenly felt. As the signal speed and sensitivity of communications and especially computer networks increased, the interference potential from any tap also went up, in linear, locked progression.
1.B. Description of the Related Art
In the field of monitoring network performance, the prior art has focused on the development, and uses, of single-purpose network taps, wherein each tap is devoted to a single analytical instrument and purpose, and devoted to a single connection, at a time. However, more and more identifying the precise nature of a connection's communications requires comparative, parallel analysis of multiple aspects of the network traffic flowing over that connection. This is particularly crucial for properly assessing and evaluating intermittent, context-dependent, or transient signal interference effects; or identifying ‘spoofing’ signals which are designed to pass a single filter test by mimicking one set of correct attributes. But this leads to a guesswork game as to which monitoring device, or which sequence of monitoring devices, should be used, for one has to know the right technical question to ask, in order to get the right type of answers.
With the increase in network traffic has also come an increase in the number, and differing natures, of problems which can afflict a network. The Internet in particular uses a packet-based protocol which presumes both a constantly changing set of network connections and that each connection is only semi-dependable. Signals can be mis-addressed, mis-routed, mis-timed, disordered, degraded, or otherwise interfered with. Connections can be formed, dropped, spoofed, or otherwise be imperfect; and they definitely change over time—sometimes, over a very short time indeed. This reduces the value of monitoring spread over time, simply because the need is to analyze multiple different aspects of a communication over a connection simultaneously, to better comprehend the condition and context affecting each particular packet. Yet single-usage network taps leave the user with either a serial-over-time analytical option, or a serial-over-communication (and thus self-interfering) analytical option, because providing multiple access required multiple taps, one for each analytical device.